1. Field of the Invention
The present invention relates to electrical engineering and, more precisely, to units of semiconductor elements.
The present invention may be applied in power supply circuits of electrical installations in matching several power supply sources differing in voltage and connected to the same load.
2. Description of the Related Art
When supplying power to electrical installations requiring current pulses with the maximum current strength of 100 to 300 kA and power of 10.sup.9 to 10.sup.11 W at a high switching frequency in low-inductance circuits the prior art units of semiconductor elements do not ensure sufficient operational reliability due to mutual induction effect with the units working simultaneously.
Widely known in the art is a unit of series-connected semiconductor elements (cf., P, Fr, No. 2,477,775), comprising a cylindrical metal case with a chain of pellet semiconductor elements enclosed therein. The chain of pellet semiconductor elements includes two sections, arranged parallel to each other. Copper inserts are located between the adjoining flat surfaces of the pellet semiconductor elements. The ends of the sections of the semiconductor element chain bear against plates functioning as clamping elements of a clamping mechanism. The clamping mechanism also contains a load-bearing element made in the form of a stud taking up the semiconductor element clamping effort, and located coaxially with the metal case. The sections of the semiconductor element chain are disposed symmetrically on both sides of the load-bearing element of the clamping mechanism. Current-carrying busbars connected ot the power supply source are associated with the outputs of the extreme semiconductor elements. Symmetric arrangement of the sections of semiconductor elements relative to the axis of the metal case produces a reverse current in the sections, which compensates the magnetic field outside the case and relieves the metal case of the action of electrodynamic forces. Due to asymmetric arrangement of the sections in a longitudinal section the compensation of the magnetic field outside the metal case is non-uniform; the compensation is minimal in the direction perpendicular to the plane containing the sections of the semiconductor element chain, which results in mutual induction effect of simultaneously operating units of semiconductor elements, worse uniformity of electric current distribution across the sections of the chain and worse relief of the case of the action of electrodynamic forces. The foregoing factors bring about lower reliability of the unit of semiconductor elements and its power capacity, and the permissible value of the pulsating current.